Does the Moon rotate as it goes around the Earth? I thought it didn't because it always keeps one face toward Earth!

The Moon definitely has to rotate to keep one face toward the Earth. If the Moon didn't rotate, we could see all parts of it as it revolved through its orbit.

Get a volunteer to be the Earth for you, and you pretend to be the Moon. Walk in a circle around the Earth, and always keep facing the Earth. Now, what do you see in the background? You'll see different parts of the room as you go around. This proves that you are rotating.

Now, try walking around the Earth without rotating; that is, always face one wall of your room as you move in a circle. Now, does the Earth only see one face of you? Or can they see all sides of you?

You can trade places, and play the Earth while the other person is the Moon, and see what happens!

Curious Minds Online

We have 8373 guests and no members online

How Many Were Here?

Total page views since 1997

87508861

Who are We?

Ask an Astronomer is run by volunteers in the Astronomy Department at Cornell University. Most of us are graduate students at Cornell, and all of us do this voluntarily, in our own time, fitting it in around our other work. Please take the time to browse our site and first try to use the resources online to find an answer to your question.